IFIS - LITORAL   24734
INSTITUTO DE FISICA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Electronic correlation e®ects on the charge exchange of Ga+ low energy ions scattered by a gold surface.
E. C. GOLDBERG; F. BONETTO; M. TACCA
Encuentro; XL Meeting of the Brazilian Physical Society; 2017
Charge exchange temperature dependence during low energy collisions can be strongly linked to electroniccorrelation e®ects if the projectile/target combination is adequately chosen. The experimental temperaturedependence of the neutralization of Ga+ ions scattered by gold polycrystalline surfaces has been previouslyattributed to purely single electron physical mechanisms. Here we extend the formalism formerly used toexplain the neutralization in the Sr+/Au system to include more than one valence states, crucial for projectileions, like Ga+, where the neutralization occurs to a p-type orbital. Two charge channels are considered: neutralGa0, with six possible con¯gurations; and positively charged Ga+. Three di®erent approximations are used:(sl) spinless, where the con¯gurations are treated independently and the electron spin is neglected; (is) whereindependent states are considered but spin °uctuation is included; and (cs) where the six Ga0 con¯gurationsare treated in a correlated way. The system is described by using an Anderson Hamiltonian projected overthe selected atom con¯guration space. We found that the correlated states treatment reproduces the measureddata, while the independent particle approach leads to an overestimation of the neutral fraction and to a nearlyconstant temperature dependence. Our results show that the proximity of the projectile one electron energylevel to the substrate Fermi level determines how important is the e®ect of the electron correlation on theneutral fraction temperature dependence.